By mid-July the sandy ground on the Glen Cove side of the harbor drains faster than the sky can refill it, and lawns show it first along the road edge. Grennan Irrigation Inc works the systems that keep that from happening: spring start-ups, head adjustment and repair, zone checks through the hot months, and winterizing before the pipes can freeze. There is real satisfaction in a properly aimed head — water on the grass, none on the driveway, an even green with no scorched corner. Watering right is half of keeping a lawn on this shore, especially where sun and salt wind meet. Glen Cove and the villages beside it make up the route.